Trigger points, also known as trigger sites or muscle knots, are hyperirritable spots in skeletal muscle that are associated with palpable nodules in taut bands of muscle fibers.
Trigger points will often cause otherwise unexplained pain that radiates from such points of local tenderness to related areas, sometimes not immediately adjacent to the trigger point itself.
Trigger points are caused by muscle exertion, overuse, repetitive stress, bio-mechanical and postural overload. Overload is when a muscle is placed in an over shortened or overstretched state for a prolonged period of time. Deep thumb or elbow pressure is applied to relief muscular pain and dysfunction causing the trigger points to deactivate.
A trigger point is described as a clinical finding with the following symptoms:                a. Pain related to a discrete, irritable point in skeletal muscle or fascia, not caused by acute local trauma, inflammation, degeneration, neoplasm or infection.        b. The painful point can be felt as a nodule or band in the muscle, and a twitch response can be elicited on stimulation of the trigger point.        c. Palpation of the trigger point reproduces the patient's complaint of pain, and the pain radiates in a distribution typical of the specific muscle harboring the trigger point.        d. The pain cannot be explained by findings on neurological examination.        
Health professionals, such as neurologist, osteopaths, orthopedic doctors, chiropractors, occupational therapists, physical therapists, acupuncturists, and massage therapists can identify trigger points as the cause of radiating or localized pain, and initiate various related treatment regimes.
The most common treatment approach is controlled application of pressure ischemic compression. Therapists will often use thumb, elbows, or simple mechanical tools to apply pressure directly upon the trigger point, in order to reduce strain on their hands. Therapists will often develop joint tenderness and injuries to hands and fingers as a consequence of long-term treatment of patients, due to the reactive forces and pressure manifesting in the arms, elbows, hands and fingers of the practitioner during trigger point treatment sessions.
The benefits of trigger point therapy include:                a. Aids in deactivating trigger points;        b. Reduces muscle contraction and muscle spasm;        c. Reduces muscle overload and pain patterns        d. Reduces adhesion and nodules;        e. Restores muscle function and regeneration;        f. Increases muscle length, flexibility and elasticity        g. Increases motor function and range of motion;        h. Increases blood flow, muscle relaxation and nutrients to localize areas        
The results of manual therapy are related to the skill level of the therapist. If trigger points are pressed for too short a time, they may activate or remain active; if pressed too long or hard, they may be irritated or the muscle may be bruised, resulting in pain in the area treated.
As such, considering the foregoing, it may be appreciated that there continues to be a need for novel and improved physiotherapeutic devices and methods for treatment of trigger points.